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Logarithm Calculator

log_base(value), plus ln and log10 of the same value. Value must be positive.

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Results

How to use Logarithm Calculator

  1. Enter value, base. Leave a field blank only when the page says the value is missing.
  2. Read the result rows under the form. Errors appear in the status line. Nothing is uploaded.
  3. Rounding follows IEEE floating point in this browser unless the page says it uses integers or BigInt.

Logarithm Calculator

Arbitrary base

Computeslog_base(value), plus ln and log10 of the same value. Value must be positive.
IncludesArbitrary base
Includesln and log10
Enginescientific
UploadNone
AdviceArithmetic only

What Logarithm Calculator is

log_b(x) = ln(x)/ln(b). Base 10 of 1000 is 3. Base e is ln. Base 1 and non-positive bases are rejected.

The formula runs in this tab. CZNull does not receive the numbers.

How this page computes

Powers are the inverse on exponent. The scientific page accepts log and ln in an expression.

Entities and related jobs

log_base(value), plus ln and log10 of the same value. Value must be positive. Named features: Arbitrary base, ln and log10.

See also Exponent Calculator, Nth Root Calculator, Scientific Calculator, Percentage Calculator, Fraction Calculator, GCD Calculator.

Use cases

pH-style logs, decibels you compute yourself, and change-of-base homework.

Limits

Invalid input appears in the status line. IEEE floating point applies unless a row says otherwise. CZNull does not receive the numbers.

Logarithm Calculator questions

Does this page upload my numbers?
No. The formula runs in the page you opened. CZNull does not receive the values.
What does Logarithm Calculator compute?
log_b(x) = ln(x)/ln(b).
Why is this its own URL?
Search queries name this job. Nearby modes stay on their own pages so inputs do not mix. Related calculators are linked below Logarithm Calculator.
log10 of 1000?
3.
Base 1?
Rejected. Log base 1 is undefined.
Can I treat the result as official?
No. Rounding and real-world rules can differ. Use the page to check the arithmetic.